Interorganizational coopetition describes a relationship in which two or more organizations cooperate and compete simultaneously. Actors under coopetition cooperate to achieve collective objectives and compete to maximize their individual benefits. Such relationships are based on the logic of win-win strategies that necessitate decision-makers in coopeting organizations to develop relationships that yield favorable outcomes for each actor. We follow a strategic modeling approach that combines i* goal-modeling to explore strategic alternatives of actors with Game Tree decision-modeling to evaluate the actions and payoffs of those players. In this article, we elaborate on the method, illustrating one particular pathway towards a positive-sum outcome – through the introduction of an intermediary actor. This article demonstrates the activation of one component in this guided approach of systematically searching for alternatives to generate a new win-win strategy. We also present a meta-model for relating i* models and Game Trees. A hypothetical industrial scenario focusing on the Industrial Data Space, which is a platform that can help organizations to overcome obstacles to data sharing in a coopetitive ecosystem, is used to explain this approach.